RNAs from pathogens inhibit plant immunity

Abstract

The present invention relates to pathogen-resistant plants comprising a heterologous expression cassette, the expression cassette comprising a promoter operably linked to a polynucleotide that is complementary to, or mediates destruction, of a plant immunity suppressing sRNA of a pathogen, wherein the plant is less susceptible to the pathogen compared to a control plant lacking the expression cassette. Methods of making and cultivating pathogen-resistant plants are also provided.

What is claimed is: 
     
       1. A pathogen-resistant plant comprising a heterologous expression cassette, the expression cassette comprising a promoter operably linked to a polynucleotide that is complementary to a plant immunity suppressing small RNA (sRNA) of a  Botrytis  pathogen or a polynucleotide that encodes a short tandem target mimic (STTM) of the sRNA, wherein the sRNA comprises the sequence set forth in SEQ ID NO:58 and wherein the plant is less susceptible to the pathogen compared to a control plant lacking the expression cassette. 
     
     
       2. The pathogen-resistant plant of  claim 1 , wherein the pathogen is  Botrytis cinerea.    
     
     
       3. The pathogen-resistant plant of  claim 1 , wherein the polynucleotide encodes a STTM of the sRNA. 
     
     
       4. The pathogen-resistant plant of  claim 1 , wherein the polynucleotide encodes an antisense nucleic acid that is complementary to the sRNA. 
     
     
       5. The pathogen-resistant plant of  claim 1 , wherein the promoter is an inducible promoter. 
     
     
       6. The pathogen-resistant plant of  claim 5 , wherein the promoter is pathogen inducible. 
     
     
       7. The pathogen-resistant plant of  claim 1 , wherein the promoter is tissue-specific. 
     
     
       8. A method of making a pathogen-resistant plant of  claim 1 , the method comprising introducing a nucleic acid comprising the expression cassette into a plurality of plants; and
 selecting a plant comprising the expression cassette. 
 
     
     
       9. An isolated nucleic acid comprising an expression cassette comprising a promoter operably linked to a polynucleotide that is complementary to a plant immunity suppressing small RNA (sRNA) of a  Botrytis  pathogen or a polynucleotide that encodes a short tandem target mimic (STTM) of the sRNA, wherein the sRNA comprises the sequence set forth in SEQ ID NO:58. 
     
     
       10. A host cell comprising the nucleic acid of  claim 9 . 
     
     
       11. The pathogen-resistant plant of  claim 3 , wherein the STTM is generated using the primer pair SEQ ID NO:438 and SEQ ID NO:439. 
     
     
       12. The isolated nucleic acid of  claim 9 , wherein the polynucleotide encodes a STTM of the sRNA. 
     
     
       13. The isolated nucleic acid of  claim 12 , wherein the STTM is generated using the primer pair SEQ ID NO:438 and SEQ ID NO:439. 
     
     
       14. The isolated nucleic acid of  claim 9 , wherein the polynucleotide encodes an antisense nucleic acid that is complementary to the sRNA.